A strut-type suspension used for front wheels of a four-wheeled vehicle generally has a structure in which a damper coil spring is combined with a strut assembly that incorporates a hydraulic shock absorber therein in an outer cylinder integrated with a main axis.
When a strut assembly rotates with a damper coil spring in a steering operation, one type of strut-type suspension rotates a piston rod of the strut assembly thereof, whereas another type of strut-type suspension doesn't rotate a piston rod of the strut assembly thereof. In both types, a vehicle thrust bearing is used between a mounting mechanism for mounting a strut assembly to a body of a vehicle and an upper end of the dumper coil spring so as to allow the strut assembly to rotate smoothly.
There is a conventional strut bearing that includes an outer wheel that is attached to a body of a vehicle having a strut-type suspension, an inner wheel that overlaps with the outer wheel so as to be rotatable with respect to the outer wheel about an axis center of a piston rod that is used for a shock absorber of the strut-type suspension of the vehicle, and a retainer that is arranged in an annular space created between the outer wheel and the inner wheel to receive a thrust load and a radial load acting from a tire (see Patent Literatures 1 and 2, for example).